Orangetheory Fitness is a one-of-a-kind, group personal training workout. The result is more energy, visible toning, and extra calorie burn for up to 36 hours. Backed by the science of Excess Post-Exercise Oxygen Consumption (or EPOC), Orangetheory’s heart rate monitored training is designed to maintain a target zone that stimulates metabolism and increases energy. We call it the after-burn. Our members burn an estimated 500 to 1,000 calories in 60 minutes.